EP3361344B1 - An aircraft autopilot system and method, and an aircraft - Google Patents

Description

The present invention relates to a system and a method for automatically piloting an aircraft, and to an aircraft provided with this system. For example, such an aircraft can be a rotorcraft, and / or an unmanned aircraft known by the acronym UAV corresponding to the English expression “Unmanned Aerial Vehicle”.

Conventionally, an aircraft comprises piloting members. The piloting devices make it possible to control the movement of the aircraft in space. These piloting units can comprise at least one motor, blades of a rotor and possibly a rotor participating at least partially in the propulsion and / or the lift of the aircraft, flaps and for example a flap arranged on a empennage or on a rudder called respectively "elevator" and "rudder" ...

The expression “piloting member” thus designates hereinafter, a member making it possible to modify the position of the aircraft in space, and possibly aerodynamic members.

An aircraft and in particular an unmanned aircraft can include an automatic piloting system making it possible to guide the aircraft along a programmed trajectory.

Such an automatic piloting system can include control members which control the piloting members. Consequently, the automatic piloting system comprises a computer which controls the control members as a function of flight data measured by various sensors. The computer can for example control the power developed by an engine, possibly by controlling a fuel injection system of this engine. The computer can also control actuators which control the position of aerodynamic surfaces in the reference frame of the aircraft. For example, the actuators can adjust the pitch of the blades of at least one rotor which participates at least partially in the lift and / or in the propulsion of the aircraft. Actuators can also adjust the incidence of at least one flap arranged for example on a wing, on a tail unit, on a fin, etc.

The computer can control the control members as a function of various constraints, such as roll / pitch / thrust yaw movement instructions, in order to follow a stored trajectory.

On a large tonnage aircraft carrying a crew, the automatic pilot systems can be sufficiently robust to comply with the design and construction standards in force in order to authorize the flight, in particular over a population. The equipment of such an automatic pilot system then has high reliability / safety levels, the reliability / safety levels sometimes being known by the acronym DAL and the English expression “Development Assurance Level”. These automatic piloting systems can then have a large mass, but reasonable with regard to the total mass of the aircraft.

In the case of a lightweight unmanned aircraft, the autopilot systems are in fact lighter. The automatic piloting systems then include equipment with lower reliability / safety levels. These automatic pilot systems may encounter difficulties in meeting design and construction standards. The components of certain automatic pilot systems make it possible to guide an unmanned aircraft on a trajectory programmed, but are not necessarily compatible in terms of reliability and safety with the standards to be respected to fly under the regulatory conditions provided for by civil aviation. A commercial flight of such an aircraft over a population is therefore likely not to be authorized.

The document FR 2 958 418 describes a flight management system for an unmanned aircraft. This document illustrates a system provided with a ground station and an unmanned aircraft.

This system provides for a flight plan construction function, a trajectory construction function and a guidance function making it possible to generate guidance instructions. Depending on the variants, certain functions are performed by the ground station or by an automatic piloting system of the aircraft. In addition, the automatic piloting system fulfills a control function by developing commands intended to control the aircraft on the basis of the guidance instructions.

The documents US4644538 , US 2007/164166 , US 5550736 and WO 2016/193884 are also known. The document US 2007/164166 is in particular far from the invention as it relates to an electrical control system called "fly by wire" and not to an automatic piloting system.

The object of the present invention is therefore to propose an innovative automatic piloting system tending to present high levels of reliability and safety, for example in order to comply with standards established by civil aviation.

The present invention therefore relates to an automatic piloting system intended for an aircraft, for example a human unmanned aircraft, according to claim 1.

The expression “several sets of redundant and independent sensors” means that the automatic piloting system comprises at least two, or even at least three sets of sensors. These sets of sensors are redundant in the sense that the sets of sensors determine at least the same data. These sets of sensors are more independent in the sense that a set of sensors does not need another set of sensors to function.

The expression “several redundant and independent calculation channels” means that the automatic piloting system comprises at least two calculation channels. These calculation channels are redundant in the sense that the calculation channels determine at least the same types of command. These calculation channels are moreover independent in the sense that a calculation channel does not need another calculation channel to function, or even does not communicate with the other calculation channels.

For example, each calculation channel can include a computer.

Alternatively, the calculation channels can represent separate channels of the same computer. Optionally, the calculation channels are respectively represented by different electronic cards of a computer, each electronic card representing a single calculation channel.

Furthermore, the control members can comprise at least one of the following members: an actuator, for example able to act on a power transmission chain connected to at least one control member, a fuel injection system, etc.

In addition, the automatic pilot system is equipped with a supervisor. This supervisor can be an independent computer, or even a sub-assembly of a computer comprising said calculation channels.

At any time, this supervisor connects at most a single calculation channel with the ordered. Only the so-called “engaged track” computation channel coupled to the control members controls these control members.

In the event of a fault in a calculation channel, the supervisor connects another calculation channel to the control units. If all the calculation channels are in a malfunction state, the supervisor may in turn command the control devices. Consequently, a failure of the first channel engaged or of the associated set of sensors is not catastrophic for the aircraft, since at least one other calculation channel can be engaged as a replacement.

A failure of the engaged track or of the associated set of sensors can be detected by the supervisor and / or a remote station by comparing the current behavior of the aircraft with a stored predictive behavior, for example before the flight. According to this variant, the trajectory of the aircraft is deterministic, this aircraft performing a programmed movement, piloted by the engaged channel. An exit from the trajectory detected makes it possible to question the integrity of this engaged channel, and to put it out of service in favor of another calculation channel.

The aircraft is thus piloted / guided by several calculation channels, only one of which is coupled to the control members, and for example to the engines of the aircraft, under the supervision of the supervisor. Only one calculation channel at a time can then generate a signal serving to control the control members.

This automatic piloting system then segregates the “piloting” function performed by the calculation channels under normal conditions, and the “supervision” function performed by the supervisor. In the event of a supervisor failure, the engaged channel continues to guide the aircraft.

This automatic piloting system thus presents a combination of multiple elements which may have a different level of regulatory requirement. Certain components of the automatic piloting system may have a relatively low reliability / safety level and others a relatively high reliability / safety level. This combination and the method applied make it possible to achieve an overall architecture tending to obtain a high level of requirement, despite the presence of devices having an average level of security.

Indeed, the supervisor is designed in such a way as to present a high level of security / reliability in order to ensure one or more of the following functions: monitoring of the sensors, creation of a consolidated sensor reference, selection of the calculation channel adequate, exclusion of the track engaged in the event of declared failure, monitoring of the flight envelope followed, monitoring of the predictive behavior of the aircraft, implementation of an emergency mode in the event of all calculation channels.

Conversely, the calculation channels and the sets of sensors can be of a known type, and can individually have a lower level of reliability and security insofar as these units are redundant and monitored by the supervisor. Relatively space-saving calculation channels and sets of sensors are thus possible.

The overall level of requirement in terms of security is finally achieved by the use of different devices, by the use of a redundant architecture and the setting up of system monitoring by a supervisor. A light automatic piloting system but having a relatively high level of reliability / safety is then conceivable, in particular for an unmanned aircraft of small dimensions.

This automatic piloting system can have an economic advantage by using components whose level of requirements is low compared to equipment having a high level of reliability / safety.

In addition, this automatic piloting system can optionally use commercial components, which facilitates its realization.

This automatic piloting system may have one or more of the following characteristics.

For example, each set of sensors can be linked to a single calculation channel or only to the supervisor.

A minimalist embodiment can include two calculation channels with their respective sets of sensors, and a supervisor with its own set of sensors.

The supervisor can establish a consolidated reference frame for the positioning and movement of the aircraft on the basis of a consistency analysis of the various sensors.

By way of example, in the presence of three satellite positioning systems, the supervisor can estimate the position of the aircraft by a usual voting method. The same goes for the movements of the aircraft.

According to another aspect, each set of sensors can include a positioning system positioning said aircraft in the terrestrial frame of reference and an inertial unit.

According to another aspect, the automatic piloting system may include a remote assembly which is not intended to be on board the aircraft, this remote assembly having a computer in communication with the supervisor via a wireless link.

The remote assembly can make it possible to monitor the position and movements of the aircraft in order to detect an anomaly, and / or can control the control members via the supervisor.

According to another aspect, the remote assembly may include a positioning device for determining the position and the movement of the on-board assembly.

For example, the remote assembly can include a radar scanning the evolution of the aircraft.

According to a variant, the monitoring of the current behavior of the aircraft is carried out at the level of a remote assembly, for example a ground station, having a high level of reliability / safety. If the remote assembly detects an exit from the trajectory or an erratic trajectory, this remote assembly can indicate to the supervisor via a wireless link, for example by radio frequency, to exclude the engaged channel then to switch to a healthy computing way. If necessary, the remote assembly can take over the piloting of the aircraft.

The invention also relates to an aircraft provided with at least one piloting member which controls a movement of the aircraft. This aircraft then comprises an automatic piloting system according to the invention, the on-board assembly being on board the aircraft.

This aircraft may have one or more of the following characteristics.

Thus, the aircraft can be an aircraft without an on-board pilot, no pilot being on board this aircraft or even no pilot piloting this aircraft.

According to another aspect, the piloting members can comprise at least one of the following members: an engine, an aerodynamic surface movable with respect to a frame of reference of the aircraft.

The invention also relates to an automatic piloting method according to claim 10.

The expression “current flight” can designate a phase going from the ignition of the engines until the stopping of the engines of the aircraft.

According to this method, the supervisor disengages the channel engaged in the presence of unforeseen behavior of the aircraft, and if necessary initiates another calculation channel.

The method may include one or more of the following characteristics.

For example, each set of sensors being able to determine data including a position of the aircraft and movement parameters illustrating / defining a movement of the aircraft, said supervisor determines a consolidated position and consolidated movement parameters by analyzing the consistency of said positions and movement parameters supplied by the sensors of the sensor sets.

For example, each set of sensors includes a satellite positioning system providing the position of the aircraft. The position of the aircraft can then be expressed by a latitude as well as a longitude and a height for example.

In addition, an inertial unit can provide parameters of movement of the aircraft, such as roll / pitch and yaw angles of the aircraft, angular speeds / accelerations as well as horizontal and vertical speeds / accelerations.

Through usual analyzes, the supervisor receives the various measured data, and deduces therefrom a consolidated position and consolidated movement parameters. A consolidated set of sensors with a vote of at least three sets of sensors can make it possible to rule out a set of faulty sensors.

In another aspect, the current behavior can be monitored by the supervisor using the consolidated position and the consolidated motion parameters.

Each calculation channel is for example programmed so that the aircraft evolves within a flight envelope with limits in attitude and angular speeds / accelerations as well as in horizontal and vertical speeds / accelerations. If one of these limits is exceeded, the channel engaged is deselected by the supervisor. An optimal choice of limits makes it possible to anticipate the fact that the aircraft is in a situation which is difficult to maintain in flight by the new channel engaged.

According to another aspect, the current behavior can be monitored by a remote assembly located outside the aircraft, the remote station indicating to the supervisor whether the committed channel must be decoupled from the control members.

According to another aspect, the supervisor can include a list prioritizing the calculation channels, said supervisor choosing the calculation channel which must be the channel engaged using said list.

For example, the supervisor first couples the first calculation channel of this list with the control devices. If the supervisor disengages this first calculation channel, the supervisor then couples the second calculation channel of this list, and so on.

According to another aspect, when the supervisor has decoupled all the calculation channels during the current flight, the supervisor can apply an emergency mode by controlling said control members himself to put the aircraft in hover while waiting for '' control by a remote unit not present in the aircraft, said remote assembly communicating with said supervisor in order to pilot the aircraft.

An emergency mode can be activated in the event of failure of all the calculation channels, or of an exit from the flight envelope that cannot be recovered by a normal stabilization method.

This emergency mode can make it possible to catch up with the vehicle in the event of an abnormal attitude, by flattening in hovering flight pending recovery by the deported assembly.

Optionally, when the supervisor has decoupled all the calculation channels, during the same flight, the supervisor can control said piloting devices to follow a preprogrammed procedure.

An emergency mode can be activated in the event of failure of all the calculation channels so that the supervisor applies an automatic procedure programmed in this supervisor. According to such an automatic procedure, the supervisor can pilot the aircraft to bring it down at controlled speed towards an emergency landing zone.

• la figure 1, un schéma illustrant un aéronef ayant un système de pilotage automatique, et
• la figure 2, un schéma illustrant un aéronef ayant un système de pilotage automatique muni d'un ensemble embarqué et d'un ensemble déporté.

The invention and its advantages will appear in more detail in the context of the description which follows with examples given by way of illustration with reference to the appended figures which represent:

• the figure 1 , a diagram illustrating an aircraft having an automatic pilot system, and
• the figure 2 , a diagram illustrating an aircraft having an automatic piloting system provided with an on-board assembly and a remote assembly.

The elements present in several distinct figures are assigned a single reference.

The figure 1 presents an aircraft 1 fitted with an automatic piloting system 20. This aircraft 1 may be an aircraft piloted by a human, or else a UAV human unmanned aircraft.

This aircraft 1 can be provided with lift surfaces, of the rotor blade 5, wing, tail, fin, flap type 7, etc. In addition, the aircraft can be provided with drive units 2, of the combustion engine type. , electric motor .... For example, the aircraft 1 comprises at least one rotor 4 provided with blades 5, the rotor being rotated by an installation comprising at least one motor.

Consequently, the aircraft 1 is provided with at least one or even at least two piloting members 10 making it possible to pilot the evolutions of this aircraft 1 in space. Such piloting members 10 can include at least one motor 2. In a complementary or alternative manner, the piloting members 10 can include at least one aerodynamic surface 5, 7 which is movable relative to a reference frame of the aircraft, such as for example a variable-pitch rotor blade 5 or a movable shutter 7.

Consequently, the automatic piloting system 20 makes it possible to act on the piloting members without the intervention of a pilot on board the aircraft.

Thus, this automatic piloting system 20 is provided with an on-board assembly 25 present in the aircraft 1. This on-board assembly 25 comprises at least one control member controlling at least one piloting member 10. Usually, a control member. control 30 may take the form of at least one actuator capable of moving an aerodynamic surface, and for example an actuator 31 of the cylinder type acting on the angle of incidence of a shutter. In a complementary or alternative manner, a control member 30 can comprise at least one actuator acting on the pitch of a blade, and for example a servo control 32 moving a blade optionally via a set of swashplates and a connecting rod. In a complementary or alternative manner, a control member 30 can comprise at least one fuel injection system 33 supplying fuel to an engine 2, or any other system making it possible to control an engine 2.

In general, the aircraft can include standard piloting members and control members without departing from the scope of the invention.

In addition, the automatic piloting system 20 comprises several calculation channels 50 independent of each other, and in particular at least two calculation channels 50. The figure 1 illustrates an autopilot system having three calculation channels 50, the figure 2 illustrating an autopilot system having two calculation channels 50.

The expression “calculation channel” designates a calculation unit, or a computer, generating control orders intended for the control members 30. Thus, each calculation channel can apply a stored algorithm to control the aircraft in order to follow a pre-programmed trajectory. The calculation channels can all be intended to transmit a signal to the same control units 30.

A computation channel may for example comprise at least one processor 51 associated with at least one memory 52, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression "calculation channel".

The calculation channels may be of a known type and may have a moderate level of security / reliability, such as for example a level known by the acronym DAL.

The calculation channels 50 can respectively be independent computers, or can jointly be parts of a computer. For example, each calculation channel is an electronic card of the same computer.

In addition and with reference to the figure 1 , the automatic piloting system 20 comprises several sets of redundant sensors 40 which are independent of one another. Each set of sensors 40 has sensors for evaluating a position of the aircraft 1 and a movement of the aircraft 1. For example, each set of sensors 40 comprises a positioning system 41 positioning the aircraft 1 in the terrestrial reference frame and an inertial unit 42.

For example, each calculation channel 50 is connected to the sensors of a single set of sensors 40 which is dedicated to it. Thus, each calculation channel can use the information transmitted by the associated set of sensors to comply with a preprogrammed flight plan.

The automatic piloting system also includes a supervisor 60. This supervisor 60 is functionally independent of the calculation channels. The expression “supervisor” designates a calculation unit, or a computer, which can in particular apply a stored algorithm making it possible to ensure that the aircraft follows the preprogrammed trajectory in the calculation channels 50

A supervisor 60 may for example comprise at least one processor 61 associated with at least one memory 62, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression “supervisor”. The supervisor can have a high DAL security / reliability level, namely higher than the reliability / security level of the computation channels 50.

The supervisor 60 may belong to a computer having the calculation channels 50. For example, each calculation channel and the supervisor are electronic cards of the same computer.

The supervisor 60 can also constitute a separate item of equipment separate from the calculation channels.

The supervisor 60 can be connected to its own set of sensors 40. This set of sensors can also have a positioning system 41 by satellites positioning the aircraft 1 in the terrestrial frame of reference and an inertial unit 42. Therefore, each sensor of a set of sensors 40 can be linked to a single calculation channel 50 or only to the supervisor 60.

The supervisor 60 makes it possible in particular to couple at each instant at most one of said calculation channels 50 to said control units 30. For example, the supervisor is connected to each calculation channel and to the control units, the supervisor transmitting only to the control units. 30 commands produced by a calculation channel. The commands produced by the other calculation channels are ignored.

By way of illustration, each calculation channel 50 can be connected to the control members 30 by a switch or equivalent. The supervisor 60 then opens all the switches except one to couple a particular calculation channel to the control devices 30.

The coupled computation channel 50 is called the “committed channel”. This engaged channel therefore generates commands transmitted to the control members 30, these commands being a function of the data transmitted by the associated set of sensors.

In addition, the supervisor 60 also has the function of decoupling the engaged channel from the control members 30 when the current behavior of the aircraft 1 is different from a predetermined predictive behavior and / or when the set of sensors of a channel calculation is faulty.

According to figure 1 , the supervisor 60 can be programmed to determine whether the current behavior of the aircraft 1 is different from a predetermined predictive behavior.

According to figure 2 , this function can be performed by a remote assembly 70 which is not on board the aircraft. This remote assembly 70 can include a computer 71 in communication with said supervisor 60 by a wireless link, such as a radio frequency link for example. The computer 71 may for example comprise at least one processor associated with at least one memory, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression "computer. 71 ”.

The remote assembly 70 may also include a positioning device 72 for determining the position and the movement of the on-board assembly. For example, this positioning device 72 can include a radar.

In a complementary or alternative manner, the remote assembly 70 can transmit commands to the supervisor 60, these commands being transmitted to the piloting units by the supervisor. The piloting of the aircraft can then be done remotely from the remote assembly.

Regardless of the variant and with reference to the figure 1 , this automatic piloting system 20 can apply the method according to the invention.

According to this method, each calculation channel 50 is programmed so that the aircraft 1 follows a particular flight plan. Likewise, the supervisor 60 and / or where appropriate the remote assembly 70 memorizes this flight plan. The aircraft must then have in space a behavior called “predictive behavior”. The expression “predictive behavior” can encompass stored data and for example a trajectory to follow and / or movement parameter limits not to be exceeded. These limits may include trim limits, and / or angular speed / acceleration limits and / or horizontal and vertical speed / acceleration limits.

Thus, the calculation channels memorize the trajectory to be followed, as well as the movement limits to be observed. The same applies to the supervisor and / or, if applicable, the remote assembly.

During a flight called “current flight”, and for example after programming and activation of the automatic pilot mode, the supervisor 60 couples a particular calculation channel 50 and the control members 30.

For example, the supervisor 60 stores a list prioritizing the calculation channels 50. The supervisor 60 then couples the first calculation channel of this list with the control members 30.

The computation channel coupled at a given instant is called “channel engaged”. The movement of the aircraft is then controlled by this engaged channel.

Consequently, the current behavior of the aircraft 1 is monitored, and compared with the preprogrammed predictive behavior. The preprogrammed predictive behavior can take the form of stored data, such as a stored path to follow, and / or low and high limits in velocities / angular accelerations to follow, and / or low and high limits in velocities / horizontal accelerations and vertical and / or trim angle limits.

According to a first embodiment, the current behavior is monitored by the supervisor 60.

For example, the supervisor 60 uses the data transmitted by the sensors 41, 42 of the set of sensors in communication with this supervisor. Using the recorded position, the supervisor 60 determines whether the aircraft is following the programmed trajectory, possibly within a position margin. In addition and using its inertial unit 42, the supervisor 60 checks that the aircraft complies with the imposed limits. For example, the supervisor checks that low and high limits in angular speeds / accelerations as well as low and high limits in horizontal and vertical speeds / accelerations are respected. If so, the supervisor considers that the current behavior is consistent with the expected predictive behavior.

Alternatively, the supervisor 60 can receive the data read by the sensors of all the sets of sensors. By a usual statistical method, the supervisor 60 determines a consolidated position and movement parameters consolidated by analyzing the consistency of the positions and of the movement parameters supplied by the sensors of the sets of sensors 40. The current behavior is then monitored by the supervisor 60 using the consolidated position and the consolidated movement parameters.

According to a second embodiment, the current behavior is monitored by a remote assembly 70 located outside the aircraft 1. Where appropriate, the remote assembly 70 indicates to the supervisor 60 whether the current behavior does not comply with the predictive behavior or whether the current behavior is consistent with the predictive behavior.

Whatever the realization and when the current behavior differs from the predictive behavior, the supervisor 60 decouples the engaged track and the piloting devices 10.

Possibly any calculation channel which was engaged during the current flight no longer be engaged again thereafter.

If at least one computation channel 50 has not been engaged during the current flight, said supervisor 60 couples such a computation channel 50 with the piloting members 10. If necessary, the supervisor can couple the computation channel which is connected. located after the channel engaged in the stored list of calculation channels.

The computation channel 50 newly coupled to the piloting units 10 becomes the new channel engaged.

On the other hand, when the supervisor 60 has decoupled all the calculation channels 50 during said current flight, the supervisor 60 can apply an emergency mode.

According to a first alternative, the supervisor 60 is programmed to itself control the control members 30. For example, the supervisor generates orders to place the aircraft 1 in hover, pending piloting by a remote assembly 70 not present in the aircraft 1. Therefore, a pilot can for example use the remote assembly 70 to remotely control the aircraft.

According to a second alternative, the supervisor 60 can control the piloting units 10 to follow a preprogrammed procedure, for example a landing procedure on a stored basis.

Of course, the present invention is subject to many variations as to its implementation. Although several embodiments have been described, it is understood that it is not conceivable to identify exhaustively all the possible modes. It is of course conceivable to replace a means described by an equivalent means without departing from the scope of the present invention.

Claims (16)

1. Autopilot system (20) for an aircraft (1), the said autopilot system (20) comprising an on-board unit (25) intended to be installed in the said aircraft (1), the said on-board unit (25) comprising at least one command component (30) intended to control at least one piloting component (10) of the said aircraft (1), which controls a movement of the aircraft (1), characterized in that the said on-board unit (25) includes:

   - a plurality of redundant and mutually independent sensor sets (40), each sensor set (40) comprising sensors (41, 42) for evaluating a position of the aircraft (1) and a movement of the aircraft (1),

   - a plurality of redundant and mutually independent calculation channels (50), the said independent calculation channels (50) not requiring another calculation channel in order to function, each calculation channel (50) being connected to the sensors of one of the said sensor set (40) and receiving data coming from these sensors,

   - a supervisor (60) connected to the sensors of one of the said sensor set (40),

   the supervisor (60) having the function of coupling at most one of the said calculation channels (50) to the said command components (30), the coupled calculation channel (50) being referred to as the "engaged channel" and being intended to generate command, which are sent to the command components (30), as a function of the said received data, the said supervisor (60) having the function of decoupling the said engaged channel from the command components when a current behaviour of the aircraft (1) is different from a predetermined predictive behaviour; when the said current behaviour differs from the said predictive behaviour, which is preprogrammed, the said supervisor (60) being configured to decouple the said engaged channel and the said piloting components (10), and, if at least one calculation channel (50) has not been engaged during the said current flight, the said supervisor (60) couples a calculation channel (50) that has not been engaged during the said flight to the said piloting components (10), this calculation channel (50) newly coupled to the piloting components (10) in turn becoming the said engaged channel;
   furthermore, the said predictive behaviour defines a trajectory to be followed and movement parameter limits not to be exceeded, the said current behaviour being different from the predictive behaviour when the aircraft (1) no longer follows the said trajectory or if at least one of the said limits is not complied with.
2. Autopilot system according to claim 1,
   characterised in that each sensor set (40) is connected to one single calculation channel (50) or only to the supervisor (60).
3. Autopilot system according to either of claims 1 and 2,
   characterised in that each sensor set (40) includes a positioning system (41), which locates the said aircraft (1) in the terrestrial reference frame, and an inertial measurement unit (42).
4. Autopilot system according to any one of claims 1 to 3,
   characterised in that the said autopilot system (20) includes a remote unit (70) which is not intended to be installed in the aircraft (1), the said remote unit (70) having a computer (71) in communication with the supervisor (60) via a wireless link.
5. Autopilot system according to claim 4,
   characterised in that the said remote unit (70) includes a positioning device (72) for determining the position and the movement of the on-board assembly.
6. Autopilot system according to claim 4,
   characterised in that the said supervisor is connected to the said calculation channels and to the said at least one command component (30).
7. Aircraft (1), provided with at least one piloting component (10) which controls a movement of the aircraft (1),
   characterised in that the said aircraft (1) includes an autopilot system (20) according to any one of claims 1 to 6, the said on-board unit (25) being installed in the aircraft (1).
8. Aircraft according to claim 7,
   characterised in that the said aircraft (1) is an unmanned aircraft.
9. Aircraft according to either of claims 7 and 8,
   characterised in that the said at least one piloting component (10) comprises at least one of the following components: a motor (2), an aerodynamic surface (5, 7) that can move relative to a reference frame of the aircraft.
10. Method for automatically piloting an aircraft with an autopilot system (20), characterised in that this autopilot system (20) is configured according to any one of claims 1 to 6,
    this method implementing the following steps during a current flight of the aircraft (1):

    - managing the progress of the aircraft (1) via one of the said calculation channels (50), referred to as the "engaged channel", the said engaged channel being coupled to the said piloting components (10) in order to command these piloting components (10),

    - monitoring a current behaviour of the aircraft (1) in relation to a preprogrammed predictive behaviour,

    - when the said current behaviour differs from the said predictive behaviour, the said supervisor (60) decouples the said engaged channel and the said piloting components (10), and, if at least one calculation channel (50) has not been engaged during the said current flight, the said supervisor (60) couples a calculation channel (50) that has not been engaged during the said flight to the said piloting components (10), this calculation channel (50) newly coupled to the piloting components (10) in turn becoming the said engaged channel;

    the said predictive behaviour defining a trajectory to be followed and movement parameter limits not to be exceeded, the said current behaviour being different from the predictive behaviour when the aircraft (1) no longer follows the said trajectory or if at least one of the said limits is not complied with.
11. Method according to claim 10,
    characterised in that, each sensor set (40) determining data including a position of the aircraft (1) and movement parameters defining a movement of the aircraft (1), the said supervisor (60) determines a consolidated position and consolidated movement parameters by analysing the consistency of the said positions and of the movement parameters provided by the sensors of the sensor sets (40).
12. Method according to claim 11,
    characterised in that the said current behaviour is monitored by the supervisor (60) by using the consolidated position and the consolidated movement parameters.
13. Method according to any one of claims 10 to 12,
    characterised in that when the said supervisor (60) has decoupled all the calculation channels (50) during the said current flight, the said supervisor (60) applies a safety mode by commanding the said command components (30) to make the aircraft (1) hover while waiting for piloting by a remote unit (70) not present in the aircraft (1), the said remote unit (70) communicating with the said supervisor (60) in order to pilot the aircraft (1).
14. Method according to any one of claims 10 to 13,
    characterised in that when the said supervisor (60) has decoupled all the calculation channels (50), the said supervisor (60) manages the said piloting components (10) so as to follow a preprogrammed procedure.
15. Method according to any one of claims 10 to 14,
    characterised in that the said current behaviour is monitored by a remote assembly (70) located outside the aircraft (1), the said remote assembly (70) indicating to the supervisor (60) whether the engaged channel should be decoupled from the command components (30).
16. Method according to any one of claims 10 to 15,
    characterised in that the said supervisor (60) includes a list hierarchising the calculation channels (50), the said supervisor (60) selecting the calculation channel which should be the engaged channel by using the said list.

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